Estimated blood loss is an important parameter recognized as a standard practice in anesthesiology and others medical specialties, with relevant clinical and research applications. Currently is no model capable of accurately estimate blood loss. The purpose of this study is to evaluate the accuracy of a novel model.

Inclusion Criteria:

• Patients scheduled for elective urologic laparoscopy surgery.

Exclusion Criteria:

• Patient with suspected or confirmed heart failure, severe hypertension, hepatic cirrhosis, chronic kidney disease on dialysis, coagulopathy, as well as patient receiving diuretics, anticoagulant or antiplatelet agents.
• Cases in which surgical gauzes were used, including conversion to open surgical technique. - Patients who have received transfusions of RBCs during the perioperative period.
• Patients who have showed postoperative bleeding, defined by an amount greater than 50 ml in surgical drains, or any other type of blood loss.

Patients scheduled for elective urologic laparoscopy surgery.